1. Field of the Invention
This invention relates to improvements in overtemperature protectors for electrically heated appliances such as flat irons. More particularly, the invention relates to spring contacts held in circuit-making engagement by a torsion spring which is, in turn, held by a fusible pin.
2. Description of the Prior Art
In general, the use of fusible members in overtemperature protectors (also referred to in the art as "thermal cut-outs") is well-known. For example, U.S. Pat. Nos. 1,015,954; 1,364,122; 1,382,101; 1,439,979; 1,468,418; and 1,556,762 shows overtemperature protectors in connection with electric irons. Other appliances having overtemperature protectors of various types are disclosed in U.S. Pat. Nos. 1,615,742; 1,693,364; and 2,022,531. The earlier patents concerned with protection against thermal overloads generally disclose space-consuming arrangements and/or devices requiring sliding elements incorporating metal-to-metal interfaces. Because of the effects of corrosion--particularly important in steam irons--these safety devices may in time degrade to the point where they will fail to function when needed. Furthermore, some of the structures disclosed incorporate the fusible element in the electrical circuit--e.g., the above-mentioned U.S. Pat. No. 2,022,531 and a more recent U.S. Pat. No. 3,665,152; but, as pointed out in the latter patent, in such case it is not permissible to have the fusible element in direct metal-to-metal contact with the outer parts of the appliance--e.g. the sole plate of an electrical iron--which the user may handle. Accordingly, there is need of an improved structure which avoids these deficiencies yet provides simple, contact, and reliable long-term protection against thermal overloads.